Prefabricated waveguide corner



PREFABRI CATED WAVEGUIDE CORNER Original Filed July 25, 1966 Sheet I of 2 June 24, 1969 R. M. WALKER PREFABRICATED WAVEGUIDE CORNER Sheet Original Filed July 25, 1986 0123121 17 walker by (wk/312637 United States Patent Int. Cl. H01p l/OZ U.S. Cl. 33398 12 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a prefabricated element which enables the manufacture at low cost and with simple techniques of a waveguide corner for use in a rectangular waveguide.

This application is a continuation of Ser. No. 567,713, filed July 25, 1966, now abandoned.

When a rectangular waveguide makes an abrupt change in direction, the change is called a corner bend. The change in direction, or corner bend, can occur at any desired angle, as little as 1 and as great as 180". Commonly such waveguide corners vary from a few degrees to 90, 90 corner bends being perhaps the most common. Waveguide corners are characterized in that the inner wall, be it a wide wall or a narrow wall of a rectangular waveguide, bends sharply along a line transverse to the wall between the two adjacent walls. The outer wall can curve, be flattened, or take any desired shape. Examples of waveguide corners are shown and described in volume 9, Radiation Laboratory series Microwave Transmission Circuits edited by Ragan, McGraw Hill Book Company, Inc. 1948, chapter 4, written by G. L. Ragan and Richard M. Walker the present inventor, section 4.12 entitled Waveguide Corners. They are shown and described also in Microwave Engineering by A. R. Harvey, published by Academic Press, Inc., 111 5th Ave., New York, N.Y., 1963, section 2.6.1 at page 76. Each of these publications shows several versions of waveguide corners having either flattened outer walls or a post compensated structure. A preferred form of structure showing a curved outer wall is shown, described, and claimed in my Patent No. 3,072,870 dated Jan. 8, 1963, the disclosure of which is incorporated herein by reference. The present invention is useful in these and other forms of waveguide corners.

In accordance with the invention, a microwave component is provided to which a pair of rectangular waveguides, cut off normal to their respective axes, can be joined, without the need of effecting any bend in either of the waveguide sections. The component of the invention comprises, in a single structure, sections of the parallel opposite walls and the outer wall of a corner. There is no inner wall. The rectangular waveguides themselves form the corner of the inner wall. At the line where the inner walls of the rectangular waveguide sections join, a notch or miter is suitable to make an electrically cOntinuous inner wall. There is thus afforded an extremely simple rigid structure of minimum size and weight, simple to construct as will presently appear, which provides all that is necessary to effect a corner bend in a rectangular waveguide of any desired configuration or change in direction.

Background of the invention Corner bend components exist which include not only top and bottom segments and outer curved or mitered wall segments, but also an inner zero radius bend segment, which define together two openings to which rectangular waveguides can be attached. The presence of 3,452,306 Patented June 24, 1969 the inner corner element portion is not only unnecessary according to the present invention, but also increases weight and size, and increases the difiiculty of final processing of components made by fine casting procedures. Thus, with the inner corner section present, especially in small waveguide sizes, if it is desired also to have an iris which may have to be trimmed, the small space which is available for hand operations makes hand trimming operations very diflicult. According to the present invention it has been found that the inner zer-o radius portion of the bend is not necessary and can be eliminated. Sutficient rigidity is afforded to the corner section component of the invention so that the outer wall will support the two parallel side walls and uninterrupted access is provided to clean out or manipulate the interior of the bend component before waveguides are aflixed to it. The resulting structure weighs less, costs less, and is more compact than any prior structure.

It is thus the principal object of the invention to provide new and improved corner bend components for rectangular waveguides. Other objects and features .are to provide such new waveguide corners that are lower in weight, easier to manufacture, less costly to manufacture, easier to trim, and easier to clean. It is a further object to provide such improved waveguide corners to which rectangular waveguide sections can be attached with a minimum of processing and with no requirement that any other bends be introduced into them.

The foregoing and other objects and features of the invention will become apparent from the following description of certain preferred embodiments of it. This description refers to the accompanying drawings wherein:

FIG. 1 is an exploded view of an H plane bend show ing the ends of two waveguide sections disposed to be coupled into it;

FIG. 1A is a cross sectional partial view of the corner formed by notching an edge of one of the two rectangular waveguide sections;

FIG. 1B is a cross sectional partial view of the corner formed by bevelling an adge of each of the two rectangular waveguide sections;

' FIG. 1C schematically illustrates an embodiment of the present invention according to my Patent No. 3,072,- 870;

FIG. 2 shows the embodiment of FIG. 1 assembled; and

FIG. 3 is an exploded view of an E plane bend, showing details similar to FIG. 1.

Referring now to FIG. 1, a .waveguide corner com ponent according to the invention is generally designated by reference character 10. This element comprises a top wall section 11, a bottom wall section 12, and an outer wall 13 joined at its periphery to the respective peripheries of the top and bottom walls 11 and 12. These walls are all rigid and therefore the structure is self supporting. The top and bottom walls 11 and 12 are wide walls of a rectangular waveguide section. A first rectangular waveguide opening '14 is defined by a first side 15 and a second side 16 bounding respectively the top wall 11 and the bottom wall 12, a third side 17 bounding the side wall 13 and a fourth side 18 indicated by a dotted line 19 running between the corners of the top and bottom walls 11 and 12. A second rectangular opening 21 is bounded by a first side 22 and a second side 23 which bound respectively the top and bottom walls 11 and 12, by a third side 24 which bounds one end of the end wall 13 and a fourth side 25 which coincides with the dotted line 19, and with the fourth side 18 of the first opening 14. It will be appreciated that the fourth side of each of the openings 14 and 21 is actually the locus of a line in a region containing no waveguide material. Each of the openings 14 and 21 lies in a plane and has a configuration such that it will receive rectangular waveguide ends 31 and 32 respectively. The planes of the openings 14 and 21 are disposed to each other at the desired angle of change-in-direction of the waveguide of which the ends 31 and 32 are parts.

FIG. 1C shows how the outer wall 13 of the present invention can be arcuately curved on a constant radius centered at a point P in the line C-C bisecting the angle between the planes of the openings 14 and 21, the point P being so located that the length of the portion X of said radius lying between the apex of said angle and said outer wall is of a preferred magnitude, of the order of ten percent less than the distance R between said apex and said third side of said opening. For a corner bend in the E plane, a preferred value of this magnitude is 0.866, in the H plane it is 0.925. A dashed line 13.3 shows the locus of an are curved on a radius equal to the distance R and centered at the intersection of the planes of the openings 14 and 21.

The openings 14 and 21 are furnished with stiffening ridges generally represented by the reference character 35 and with coupling flanges 36 at the wide walls and 37 at the end walls to facilitate joining the waveguide ends 31 and 32 with the corner component 10.

The waveguide ends 31 and 32 are simply the ends of rectangular waveguides cut off normal to the longitudinal axis. In order to facilitate the formation of an electrically continuous corner, the end 31 of one of the waveguides is notched as at 31.5 so that the adjoining corner 32.5 which is not notched can fit into it. A detail sketch at FIG. 1A shows how this structure is assembled. An alternate procedure, illustrated in FIG. 1B, for fabricating a good corner consists of forming bevels 31.6 and 32.6 at the meeting edges of the inner walls of both waveguides 31 and 32 so that the inner walls of the two waveguides form an electrically continuous corner when they are joined at the desired angle. The two waveguides are joined in a plane 38 by such methods as brazing or welding; and at notch 31.5 and corner 32.5.

FIG. 2 shows the entire corner assembled to form a 90 bend in a rectangular waveguide. Only the minimum required number of reference characters has been shown in FIG. 2, so that it can be compared easily with FIG. 1. It will be immediately appreciated that the corner bend which is afforded by the present invention is as small and light in weight as any that can be made in the present state of the art. The component is simple to fabricate and, since there is no structural material along the line of the corner represented by the dotted line 19, it is very simple to insert tools such as polishing devices including rotating brushes to fabricate or trim the interior of the bend. This bend can be precision cast, of aluminum or brass for example, or can be machine fabricated as desired, there being no difficulty in choosing any form of fabrication. Moreover, especially where it is desired to fabricate a waveguide bend according to my Patent No.

3,072,870, where the radius of curvature of the side wall 13 is centered at a point outside the structure 10, it is a simple matter to employ a rotating element centered at a point outside the structure to trim the interior of the curved wall 13.

Referring now to FIG. 3, an E plane bend similar to the H plane bend of FIGS. 1 and 2 is shown. The component 40 has first and second Similar rectangular waveguide openings 41 and 42 at planes disposed to each other at the desired angle of change in the direction of the waveguide as represented by waveguide ends 43 and 44. These planes intersect each other along a line in the corner of the bend, represented by the dashed line 45 extending between the top narrow wall 46 and the bottom narrow wall 47 of the component 40. First narrow sides 41.2 and 42.2 of the openings 41 and 42, respectively, define boundaries of the top wall 46. Second narrow sides 41.2 and 42.2 of the openings 41 and 42, respectively, define boundaries of the bottom wall 47. Third sides 41.3 and 42.3 are long sides of the openings 41 and 42, respectively, and define ends of the outer wide wall 48 of the component 40. The fourth side of each opening 41 and 42 is located substantially coincident with the dashed line 45, where the component 40 is open and without waveguide material. The component 40 is desirably fitted with stiffening ridges 35 and coupling flanges 36 and 37, like the embodiment of FIG. 1. The waveguide ends 43 and 44 will be treated in the manner of FIG. 1A or 1B, for example, in order that the similar inner wide walls 53 and 54 may make a continuous electrical junction in the corner at the dashed line when assembled to the component 40.

While the invention has been described in relation to specific embodiments, various modifications thereof Will be apparent to those skilled in the art and it is intended to cover the invention broadly within the spirit and scope of the appended claims.

I claim:

1. For use in effecting a change in the axial direction of a rectangular waveguide transmission line, a bent rectangular waveguide section of zero inside radius having first and second similar rectangular waveguide openings at planes disposed to each other at the desired angle of said change and intersecting each other along the line in the corner of the bend, first and second similar sides of each of said walls meeting respectively at said line, a first and second parallel planes defining boundaries of two spaced apart walls of said section, said boundaries of each of said walls meeting respectively at said line, a third side of each opening being disposed between the first and second sides thereof remote from said line, said section being open and without waveguide material in said line, said section having an outer wall extending between said third sides, said two spaced apart walls meeting said outer wall along their respective peripheries and constituting therewith the only walls of said waveguide section.

2. A bent rectangular waveguide section according to claim 1, including means for joining a rectangular waveguide to each of said two rectangular waveguide openrugs.

3. A bent rectangular waveguide section according to claim 1 in which said outer wall is arcuately curved on a constnat radius centered at a point in the line bisecting the angle between said planes.

4. A bent rectangular waveguide section according to claim 3 in which said point is so located that the length of the portion of said radius lying between said apex of said angle and said outer wall is of the order of ten percent less than the distance between said apex and said third side of said opening.

5. A bent rectangular waveguide section according to claim 1 in which said desired angle is substantially ninety degrees.

6. A bent rectangular waveguide section according to claim 1 in the E plane, having first and second shorter sides of said openings disposed, respectively, in first and second parallel planes defining the narrow walls of said section and a third longer side which is Opposite the apex of said angle.

7. A bent rectangular waveguide section according to claim 6 in which the distance from said apex to said outer wall along the bisecting line of said angle is ap- 'proximtaely 0.866 of the distance between said apex and said third longer side.

8. A bent rectangular waveguide section according to claim 1 in the H plane, having first and second longer sides of said openings disposed, respectively, in front and second parallel planes defining the wide walls of said section and a third shorter side which is opposite the apex of said angle.

9. A bent rectangular waveguide section according to claim 8 in which the distance from said apex to said outer wall along the bisecting line of said angle is approximately 0.925 of the distance between said apex and said third shorter side.

5 6 10. The combination of a bent rectangular waveguide said joining means consist of a bevel in said meeting walls section according to claim 1 and first and second rectangllof both of said rectangular waveguides so cut that when lar waveguide sections each having an open end with the two rectangular Waveguides are joined together at the said open end joined to a respective one of said opendesired angle a continuous electrical contact is formed ings, similar fourth side walls of said waveguides meet- 5 between said meeting walls. ing substantially along said line in the comer of the bend,

and means providing continuous electrical contact be- References Cited tween said meeting walls in said corner. 11. A combination according to claim 10 in which said joining means consists of a notch in said meeting wall of 2291331 6/1880 Orphy 285 183 one of said rectangular waveguides so cut that when the 10 3,072,870 1/1963 Walkertwo rectangular waveguides are joined together at the desired angle a continuous electrical contact is formed be- HERMAN KARL SAALBACH Pnmary Examme" tween said meeting walls. Z. ALLAHUT, Assistant Examiner.

12. A combination according to claim 10 in which 15 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,452, 306 une 24, 1969 Richard M. Walker It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 40, "adge should read edge Column 3, line 71, "41.2 and 42.2" should read 41.1 and 42.1 Column 4, line 26, after "said' first occurrence, insert openings being disposed respectively in first and second parallel planes defining boundaries of two spaced apart walls of said section, said boundaries of each of said line 43, "constnat" should read constant lines 62 and 63, approximtaely" should read approximately line 67, "front" should read first Signed and sealed this 21st day of April 1970.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer 

